The most common and most likely answer to this crossword clue is the 8 letter word TOGETHER
I've seen this crossword clue in Independent
T
O
G
E
T
H
E
R
More clues leading to the result TOGETHER
- To see the girl in one place
- First parts of this old Gershwin number in concert
- As one wearing tie, proceed to the left
- How we may combine to collect present, in short
- Calm there got disturbed
- . Obtained back number at the same time
- Caught up with three playing in concert
- What suitor might want in company
- Turn up, wearing tie, having a common plan
- Got over there cycling at the same time
Buddy explains!

The straight part
We know that "at the same time" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case at the same time = together.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does TOGETHER mean?
TOGETHER adjective- Coherent; well organized.
- At the same time, in the same place; in close association or proximity.
- Into one place; into a single thing; combined.
- In a relationship or partnership, for example a business relationship or a romantic partnership.
- Without intermission or interruption; continuously; uninterruptedly.